Revolutionizing 3D Printing: Harnessing the Power of Lignin-Based Ink for Versatile Applications

Lignin, derived from renewable reservoirs such as straw, wood, and lignocellulosic plant material, stands as the second most prevalent biopolymer and is a pivotal component in advanced additive manufacturing. This review encompasses recent studies that have contributed to the elucidation of innovative ink formulations of lignin-based composites, particularly within the framework of Direct Ink Writing (DIW) for fabricating high-performance printed objects. These composites play a crucial role in reducing dependency on traditional petroleum-based materials, aligning with sustainable manufacturing practices, and addressing environmental concerns prevalent in conventional manufacturing methods. The challenges encountered with using composites made of lignin, particularly in addressing rheological limitations and nozzle clogging when combined directly with solvents or water, serve as focal points for strategic innovation. Through the integration of Cellulose Nanofibrils (CNF), viscoelastic polymers, and carbon-based additives with unique flow properties, these challenges are effectively navigated, unlocking new frontiers for the application in additive manufacturing of lignin-based composites. Furthermore, the review sheds light on the diverse industrial applications of 3D printed lignin composites, spanning the electronics, biomedical, environmental remediation, and photoelectrochemical hydrogen evolution sectors. The review concludes by casting a spotlight on the future scope and potential avenues for leveraging lignin-based composites in additive manufacturing, thereby emphasizing the imperative for sustainable innovation and the diversification of industrial applications in the dynamic landscape of 3D printing.